The 28-year-old had never been to St Andrews before this week but made the most of a practice round with Watson on Tuesday.
While the five-time Open champion, playing in the tournament for the last time, could only manage a four-over 76 on Thursday, Streb took full advantage of decent morning conditions to post the early clubhouse lead, making seven birdies in his round of 66.
“I tried to get as much information as I could – he was pretty helpful,” said Streb, who won the McGladrey Classic in 2014 and only played in his first major championship in the Masters earlier this year.
“He’s obviously had a great track record over here. I tried to arrange it last week and luckily he was nice enough to play. I live in Kansas City and he lives there as well, but I knew this week would be very busy for him. He has a lot going on.
“Probably the best thing I got was try not to hit it too far into the green on 17. Just try to get it up there on top and take your two putts and leave.”
Streb made just one mistake, bogeying the 10th, but he bounced back with two more birdies on the back nine after going out in 31 and is expecting a different challenge on Friday when the weather is forecast to worsen.
“I had that wind helping off the right on the way out, so that’s nice for a right-handed golfer and I tried to take advantage of the holes on the way out and made some good putts,” he added.
“There was one little hiccup on 10, but other than that, I played pretty solid. Luckily you can miss a lot of shots to the left out here. It’s been really cool. Really enjoyed everything about it.
“I’m sure it won’t be very easy. I haven’t had the pleasure of playing this place in real heavy wind yet, but I’m sure it will be a treat, and it’ll be entirely different for me on Friday.”